good looking hand.. I especially like the colour scheme, makes it look like a negative. Kudos for that. And what kind of slime effect are you going for? cuase it looks like some intelligent slimy thing is taking over the hand by growing little bits that wind their way around his fingers.... as opposed to a hand that's been dipped in or had slime poured over it. For some reason, it reminds me of how Venom would look in mid-change with the symbiote coating his body. I think I read too many comics....

The concept here was for the hand to have penetrated a plasma surface, not organic slime, but not exactly inanimate either...
It was just airbrushed, though the highlights were done on a layer set to hard light. The trickiest bit was getting the shape of the slime to look anything like right.
The light sources are at the top, bottom and right sides of the hand. That's why the slime, too is highlighted at most edges.
I think the highlights ion the center of the slime may be a bit too harsh, though. Well, I noticed some flaws anyhow, and I'm fixing them now, might as well do something about that as well.
I'm not sure I could get away with a shadow, since the lights are pretty harsh. I think they'd negate any shadows cast by the slime. Maybe I should try a refracted light-type of thing, though.